Change throw AssertionError to error() that throws IllegalStateException

as ISE is more appropriate exception for validation.

Improve SerializerClassLowering.runPluginSafe so precise IrClass
where plugin have failed can be reported for non-fatal errors.

#KT-55296 Fixed

plugins/kotlinx-serialization/kotlinx-serialization.backend/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/BaseIrGenerator.kt

@@ -87,7 +87,7 @@ abstract class BaseIrGenerator(private val currentClass: IrClass, final override
                 { serializerSymbol ->
                     val kotlinType = (serializerSymbol.owner.superTypes.find(IrType::isKSerializer) as? IrSimpleType)?.arguments?.firstOrNull()?.typeOrNull
                     val classSymbol = kotlinType?.classOrNull
-                        ?: throw AssertionError("Argument for ${SerializationAnnotations.additionalSerializersFqName} does not implement KSerializer or does not provide serializer for concrete type")
+                        ?: error("Argument for ${SerializationAnnotations.additionalSerializersFqName} does not implement KSerializer or does not provide serializer for concrete type")
                     classSymbol to kotlinType.isNullable()
                 },
                 { it }
@@ -372,7 +372,7 @@ abstract class BaseIrGenerator(private val currentClass: IrClass, final override
         cacheableSerializers.firstOrNull { it != null } ?: return null
 
         val kSerializerClass = compilerContext.kSerializerClass
-            ?: throw AssertionError("Serializer class '$KSERIALIZER_NAME_FQ' not found. Check that the kotlinx.serialization runtime is connected correctly")
+            ?: error("Serializer class '$KSERIALIZER_NAME_FQ' not found. Check that the kotlinx.serialization runtime is connected correctly")
         val kSerializerType = kSerializerClass.typeWith(compilerContext.irBuiltIns.anyType)
         val arrayType = compilerContext.irBuiltIns.arrayClass.typeWith(kSerializerType)
 

plugins/kotlinx-serialization/kotlinx-serialization.backend/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/IrBuilderWithPluginContext.kt

@@ -170,7 +170,7 @@ interface IrBuilderWithPluginContext {
         val irBlockBody = irBlockBody(startOffset, endOffset, blockBuilder)
         irBlockBody.statements.dropLast(1).forEach { +it }
         return irBlockBody.statements.last() as? IrExpression
-            ?: throw AssertionError("Last statement in property initializer builder is not an a expression")
+            ?: error("Last statement in property initializer builder is not an a expression")
     }
 
     fun IrBuilderWithScope.irInvoke(

plugins/kotlinx-serialization/kotlinx-serialization.backend/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/IrPredicates.kt

@@ -122,7 +122,7 @@ fun IrClass.serialName(): String {
 
 fun IrClass.findEnumValuesMethod() = this.functions.singleOrNull { f ->
     f.name == Name.identifier("values") && f.valueParameters.isEmpty() && f.extensionReceiverParameter == null && f.dispatchReceiverParameter == null
-} ?: throw AssertionError("Enum class does not have single .values() function")
+} ?: error("Enum class does not have single .values() function")
 
 internal fun IrClass.enumEntries(): List<IrEnumEntry> {
     check(this.kind == ClassKind.ENUM_CLASS)

plugins/kotlinx-serialization/kotlinx-serialization.backend/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/SerializableIrGenerator.kt

@@ -401,7 +401,7 @@ class SerializableIrGenerator(
                     hasSerializableOrMetaAnnotationWithoutArgs() && !isInternalSerializable && !hasCompanionObjectAsSerializer && kind != ClassKind.ENUM_CLASS && !isSealedSerializableInterface
                 }
                 if (serializableAnnotationIsUseless)
-                    throw AssertionError(
+                    error(
                         "@Serializable annotation on $irClass would be ignored because it is impossible to serialize it automatically. " +
                                 "Provide serializer manually via e.g. companion object"
                     )

plugins/kotlinx-serialization/kotlinx-serialization.backend/src/org/jetbrains/kotlinx/serialization/compiler/extensions/SerializationLoweringExtension.kt

@@ -106,13 +106,16 @@ class SerializationPluginContext(baseContext: IrPluginContext, val metadataPlugi
 private inline fun IrClass.runPluginSafe(block: () -> Unit) {
     try {
         block()
-    } catch (e: Exception) {
+    } catch (e: Throwable) {
-        throw CompilationException(
+        throw when (e) {
-            "kotlinx.serialization compiler plugin internal error: unable to transform declaration, see cause",
+            is VirtualMachineError, is ThreadDeath -> e
-            this.fileParent,
+            else -> CompilationException(
-            this,
+                "kotlinx.serialization compiler plugin internal error: unable to transform declaration, see cause",
-            e
+                this.fileParent,
-        )
+                this,
+                e
+            )
+        }
     }
 }
 
@@ -163,7 +166,9 @@ open class SerializationLoweringExtension @JvmOverloads constructor(
 
     private var intrinsicsState = SerializationIntrinsicsState.NORMAL
 
-    constructor(metadataPlugin: SerializationDescriptorSerializerPlugin, intrinsicsState: SerializationIntrinsicsState) : this(metadataPlugin) {
+    constructor(metadataPlugin: SerializationDescriptorSerializerPlugin, intrinsicsState: SerializationIntrinsicsState) : this(
+        metadataPlugin
+    ) {
         this.intrinsicsState = intrinsicsState
     }